Patients receive induction therapy comprising prednisone orally or IV three times a day on days 1-7; dexamethasone orally or IV three times a day on days 8-35; vincristine IV on days 8, 16, 22, and 30; cytarabine IV over 30 minutes on days 8-21; daunorubicin IV over 60 minutes on days 8 and 9; asparaginase IV over 1 hour or intramuscularly (IM) on days 15, 18, 22, 25, 29, and 33; methotrexate intrathecally (IT) on days 1 and 29; and cytarabine IT on day 15. Patients receive prednisolone IT in combination with any dose of intrathecal chemotherapy. Patients with CNS involvement receive additional doses of methotrexate IT on days 8 and 22 and then weekly after day 29 until there is no evidence of CNS leukemia.